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Please Help: Dovecot ssl_ca selection based on remote IP address filtering not working.
by Sean Gallagher 11 Feb '23

11 Feb '23

Hi All, I hope this is the correct place to post this. If not, apologies. I am in the process of updating my company's email servers and am trying to put Dovecot into an Alpine Linux container, hosted on ProxMox. In my setup, local mail deliveries via LMTP can come from the MSA (for intra-company mail) and an MTA (for inbound mail). The LMTP data is sent over IPv4 and is protected by TLS. Client certificates are used to authenticate sources. I wanted to prevent Dovecot from accepting LMTP from any other source and the method I came up with to do this was to use filtering on the "remote" address. I would create a "Fake" CA that had never signed a certificate and use that to evaluate the certificate presented by incoming connections from addresses other than the two legitimate sources. This would cause all connections from "bad" addresses to be rejected. This seemed simple enough on paper but Dovecot just isn't playing along. It seems that no matter what I do, I cannot get "remote" filtering to switch the "ssl_ca" parameter. I have put together a test bed to demonstrate. I then use openssl s_client to attempt to connect to the test bed container. I've attached the instructions to build the test bed from scratch. In all cases s_client reports "Acceptable client certificate CA names" "CN = Fake CA" I.e. it want's a certificate from the CA that has never signed a certificate and never will. Why not do the obvious thing? I use LDAP to authenticate individual users and the user name will be reported over LMTP. So to use the normal authentication mechanisms to authenticate the connection source, I would need to do two LDAP lookups, one for the connecting machine and one for the mail recipient. It is not clear if this is possible from the documentation.. *Questions:* Is config file filtering broken or am I doing it wrong? Is it possible to provide a different "ssl_ca" based on the remote IP address? Is there an easier way to restrict LMTP connections to specific remote IP addresses? p.s. Filtering just doesn't work like it's supposed to. Someone should look at that (especially multi-level) .. See this: https://dovecot.org/pipermail/dovecot/2016-June/104770.html Any help would be greatly appreciated. I am at my wits' end with this. -- This email has been checked for viruses by AVG antivirus software. www.avg.com

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Why does creating a mailbox create it in all namespaces?
by e 10 Feb '23

10 Feb '23

When I create a mailbox using CREATE, it creates it in all namespaces? Is that supposed to happen? Look: ``` a namespace * NAMESPACE (("" "/")("Other/" "/")) NIL NIL a OK Namespace completed (0.001 + 0.000 secs). a list "" * * LIST (\HasNoChildren) "/" Other * LIST (\HasNoChildren) "/" INBOX a OK List completed (0.001 + 0.000 secs). a create Other/Drafts a OK Create completed (0.003 + 0.000 + 0.002 secs). a list "" * * LIST (\HasNoChildren) "/" Drafts * LIST (\HasChildren) "/" Other * LIST (\HasNoChildren) "/" Other/Drafts * LIST (\HasNoChildren) "/" INBOX a OK List completed (0.001 + 0.000 secs). ``` This is my namespace configuration ``` namespace { prefix = inbox = yes separator = / } namespace { prefix = Other/ separator = / } ``` And dovecot version is 2.3.7.2

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doveadm: Error: Mailbox INBOX: Deleting corrupted cache: Cache file too large
by Ralf Hildebrandt 09 Feb '23

09 Feb '23

Hi! Upon issuing a % doveadm import -u restore(a)backup.invalid mdbox:/home/storage/mdbox I'm getting a: doveadm(restore(a)backup.invalid): Error: Mailbox INBOX: Deleting corrupted cache: Cache file too largea doveadm(restore(a)backup.invalid): Error: Corrupted dbox file /home/restore/mdbox/storage/m.7 (around offset=41602004): msg header has bad magic value doveadm(restore(a)backup.invalid): Error: Corrupted dbox file /home/restore/mdbox/storage/m.8 (around offset=17193748): msg header has bad magic value message -- but the process keeps running! Should I worry? dovecot packages: 2.3.20-3+ubuntu20.04 -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebrandt(a)charite.de | https://www.charite.de

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Pigeonhole Sieve Vacation Reply-To peculiarity with inbound AWS-SES
by Dr. Rolf Jansen 08 Feb '23

08 Feb '23

To begin with, usage of Amazons Simple Email Service (SES) is mandatory for outgoing mails from AWS-EC2 instances. The Pro is, it does work and we may utilize email relays with high reputation for our outgoing mails at no additional costs. The Con's are that (A) SES does not relay mails with empty <> MAIL FROM addresses and (B) it fiddles with the envelope addresses of the relayed mails. Anyway this is out of our control, and while I could avoid (A) by switching the e-mail service provider, I still have no control over (B) because this affects replying to emails from others using AWS-SES. Problem A) The empty-MAIL-FROM may be effectively addressed by setting Pigeonhole’s sieve_vacation_send_from_recipient to ‚yes‘. Problem B) Pigeonhole Vacation utilizes the senders envelope address of the inbound message as the reply-address. The problem here is that inbound mails from third parties utilizing AWS-SES come in with an unpersonalized envelope address and SES takes returns to this as bounce messages and changes the body's From: to „MAILER-DAEMON(a)xx-zzzz-1.amazonses.xn--com-5o0a, which is not even our MAILER-DAEMON but the one of the receiver of our reply. So the receiver gets no chance to know from the headers the identity of whom replied - he may assume it from the context the actual message, though. I found the setting sieve_vacation_to_header_ignore_envelope, which was introduced in 2017 (https://dovecot.org/list/dovecot-cvs/2017-August/028917.html) My finding is, that this resolves the problem only half way. For a local workaround, I changed Line 1119 of cmd-vacation.c https://github.com/dovecot/pigeonhole/blob/34431d7a67474c00d5b0554f5d45b867… to: struct smtp_address real_to; if (smtp_address_init_from_msg(&real_to, &reply_to) >= 0) sctx = sieve_smtp_start_single(senv, &real_to, smtp_from, &output); else sctx = sieve_smtp_start_single(senv, smtp_to, smtp_from, &output); That in place and setting sieve_vacation_to_header_ignore_envelope to ‚yes‘, effectively resolves problem B as well. Best regards Rolf Jansen

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Ubuntu packages for 22.04 LTS?
by Ralf Hildebrandt 06 Feb '23

06 Feb '23

Hi! I recently updated from 20.04 -> 22.04 and wondered if packages specifically for 22.04 were available. https://doc.dovecot.org/installation_guide/dovecot_community_repositories/u… doesn't seem list any... Neiter does https://repo.dovecot.org -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebrandt(a)charite.de | https://www.charite.de

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problem converting mailbox to maildir with doveadm
by Kenneth Irving 05 Feb '23

05 Feb '23

Hello. I have an email server for testing purposes, using postfix 3.5.17 and dovecot 2.3.13. Initially, I configured postfix to use mailboxes, but now I've changed it to maildir. Emails arrive fine, and dovecot manages them well by pop3 or imap. No problems there. But I still have a lot of emails in different mailboxes which I'd like to convert to maildir. I found mb2md, which seems to do a pretty good job. Once the mailbox is converted, dovecot manages the emails without a problem. But I also wanted to learn how to use doveadm to convert mailboxes to maildir format. I read all the documentation I could find and tried to learn how this command works. I tried different combinations, but couldn't convert mailboxes to maildir. I always get error messages. I've been unable to understand why. I tried to sync, backup, and import, to no avail. I also tried dsync, which seems to have a different syntax, with the same result. Sorry for bothering you, but if you could explain to me how this command works, I'd be very grateful. Example: I have a user, let's say joe, who has a mailbox in /var/mail/joe and I'd like to transfer those emails to /home/joe/Maildir How do I use doveadm in this situation? Best regards Kenneth

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IMAP tuning for Outlook 365
by Artur Pydo 02 Feb '23

02 Feb '23

Hello, I'm looking for advices on IMAP config tuning for best user experience with Outlook 365. I'm currently using dovecot 2.3.4.1 (f79e8e7e4) provided with Debian 10. One of my users has Outlook 365 and an IMAP mailbox of large size with several folders (more than 3GB). From time to time as his main inbox folder is growing he can see some problems with its Outlook application. Sometimes it freezes during mailbox synchronisation, sometimes he can't see new incoming emails. I wonder if there is some specific workarounds for an up-to-date Outlook in Dovecot or if you can suggests some config setup adjustments (timeouts, idleing ...) to avoid problems in his Outlook. Most of the config are defaults. But I can provide relevant parts of the config if needed. I have this workaround activated for a long time: imap_client_workarounds = delay-newmail By the way, I also have a big IMAP mailbox. Can't see any server specific problem while connecting with Thunderbird to this Dovecot server. -- Best regards, Artur

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Dovecot gzip u.files on sdboxes
by Jose Celestino 01 Feb '23

01 Feb '23

Hi, I was wondering if it's possible to lighten the process of converting sdbox mailboxes to zlib by, instead of using dsync (that brings much more io, copying from alt - and copying of unneeded data as we have many mails already compressed from activating zlib a couble of years ago) just compressing each of the u files. By compression of the u files I mean opening the uncompressed u file for reading, a u.temp file for writting and: 1. copy the dbox message header from u to u.tmp 2. compress the plain message and write it to u.tmp 3. fix the message_size_hex on the u.tmp dbox message header to the new, compressed size 4. copy the dbox metadata from u to u.tmp with Zphysical_size added 5. copy the u stat times to u.tmp 6. replace u with u.tmp Is the message_size_hex stored anywhere else (indexes) that may cause this to not work? Thank you.

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Add Userdb extra field to existing configuration settings, not overriding them
by Stefano Cecconello 27 Jan '23

27 Jan '23

Hi, If i understood correctly the extra field feature ( https://doc.dovecot.org/configuration_manual/authentication/user_database_ex tra_fields/ ), any extra field that is passed from a SQL query will overwrite any existing settings on the dovecot.conf configuration file ( if present ) . For example, if i want to enable a plugin ( ex: acl ) on a per user basis, i would add a column\field ( ex: "acl_enabled" = 1 ) into my auth DB , then add into the dovecot password\user queries : . IF(acl_enabled = 0, NULL, 'acl imap_acl') AS mail_plugins . While having in the dovecot.conf this setting : . mail_plugins = quota notify protocol imap mail_plugins = $mail_plugins imap_quota . >From my test, this combination will lead to having the logging users with acl_enabled=1, a mail_plugins list of acl and imap_acl only, without the quota and notify plugins . If i change the acl_value to 0, the returned mail_plugins list is empty and it will not overrive\overwrite the dovecot.conf mail_plugins configuration . If it's correct, there is a way to merge both settings, like having in the dovecot.conf a minimal\base subset of settings and adding any additional values via SQL queries ? Thanks and best regards Stefano

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sieve_extprograms plugin calling bash script
by Tom 27 Jan '23

27 Jan '23

I receive an email a few times a week containing a URL for a live stream which starts within a minute after receiving the email. I want to automate capturing the whole stream. I've been trying to write a sieve script which uses the sieve extprograms plugin to call a bash script that parses the URL from the email and passes it to a capture program. So far I've had no luck getting the bash script to call _any_ external programs. I can't even write a file to /tmp/, so it's not a filesystem permissions issue. The sieve script has no issues finding and executing the bash script, it just does nothing other than return an exit code. Does sieve put the extprogram script in some kind of sandbox where it has no access to the system? This may not be the best place to find answers to sieve plugin info. If so, can someone point me in the right direction?

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